Jewelry and other objects often require a device that allows two ends of the object to be repeatedly fastened and unfastened. The object, if a necklace or bracelet, requires two ends of the object to be fastened so that it can be secured around the neck or wrist of the wearer. If an earring or pin, the object must be capable of securing between two ends, a piece of clothing, an ear lobe, and the like. A device that is able to fasten the opposite ends of such objects may be called a clasp. Various methods exist for forming this clasping device. One well known and popular method uses a mechanical clasp.
An alternate method is to use a magnetic force to form the clasp. In such a method, two magnets are fastened to opposing ends of a piece of jewelry. Each magnet has a north and a south pole. Preferably, the south pole face of one magnet and the north pole face of the other magnet form the clasp interface. When the magnets are brought together, the attractive magnetic force of the opposing north and south pole faces forms the clasp. The attractive force of these clasps is strongest in the direction perpendicular to the interface region where the two clasp magnets come into contact. The magnetic force in the direction parallel to the interface area is much weaker.
Because of this significant difference in the amount of attractive force at the interface between two magnets that form a clasp, it has been found that conventional magnetic clasps are difficult to open because of the strong magnetic force that exists in a direction perpendicular to this interface.
As seen in the prior art patents to Hornick U.S. Pat. No. 2,615,227 and Fujimoto U.S. Pat. No. 4,231,137, magnetic clasps may have opposing male and female pieces to provide a mechanical resistance to the application of a force in a direction parallel to the clasp interface. In such a method, small forces parallel to the interface will not separate the clasp. However, these prior art mating clasp structures suffer from the disadvantage that they cannot prevent the separation of the clasp due to a force in any direction in the plane of the clasp interface. Ordinarily, the mechanical resistance is to a force in only one direction.
Further, conventional magnetic clasps do not provide adequate safety mechanisms to guard against loss of the jewelry, should the clasp accidentally release.